Aum Shinrikyo gained official status as a religious organisation in Japan in 1989 and picked up a sizeable global following.

The group gradually became a paranoid doomsday cult, convinced the world was about to end in a global war and that only they would survive.

The cult went underground after the 1995 attack, but did not disappear, renaming itself Aleph or Hikari no Wa.

Aum Shinrikyo is designated a terrorist organisation in the US and many other countries, but Aleph and Hikari no Wa are both legal in Japan, although designated as "dangerous religions" subject to surveillance.